// Copyright 2004-2008 Castle Project - http://www.castleproject.org/
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

namespace Castle.Windsor.Adapters.ComponentModel
{
	using System;
	using System.ComponentModel.Design;
	
	using Castle.MicroKernel;
	using Castle.MicroKernel.ComponentActivator;
	using Castle.Core;

	/// <summary>
	/// Custom activator to create the instance on demand.
	/// </summary>
	internal class ServiceCreatorCallbackActivator : AbstractComponentActivator
	{
		public static readonly String ServiceContainerKey = "serviceContainer";
		public static readonly String ServiceCreatorCallbackKey = "serviceCreatorCallback";

		public ServiceCreatorCallbackActivator(ComponentModel model,
		                                       IKernel kernel, ComponentInstanceDelegate onCreation,
		                                       ComponentInstanceDelegate onDestruction) :
		                                       	base(model, kernel, onCreation, onDestruction)
		{
			// Nothing to do
		}

		protected override object InternalCreate(CreationContext context)
		{
			IServiceContainer container = (IServiceContainer)
				Model.ExtendedProperties[ServiceContainerKey];

			ServiceCreatorCallback callback = (ServiceCreatorCallback)
				Model.ExtendedProperties[ServiceCreatorCallbackKey];

			Type serviceType = Model.Service;
			object service = callback(container, serviceType);

			if (!(service == null || service.GetType().IsCOMObject ||
				serviceType.IsAssignableFrom(service.GetType())))
			{
				service = null;
			}

			return service;
		}

		protected override void InternalDestroy(object instance)
		{
			// Nothing to do
		}
	}
}
